More than ever, climate protection is a topic of great relevance. One effort in this field is directed to reduce fuel consumption of vehicles and to consequently lower emission of greenhouse gases such as carbon dioxide by decreasing the weight of a vehicle. Yet, in vehicles, safety aspects and consumer demands require sophisticated electrical wiring leading to an increase in vehicle weight. In order to satisfy both, climate protection and low vehicle weight, lightweight materials such as aluminum may be employed for electrical wiring. However, aluminum is prone to oxidation, when exposed to oxygen from ambient air, which will create a thin layer of electrically insulating aluminum oxide. As a consequence electrical conductivity will be lowered, which, for example, may lead to malfunction of an electronic device fed via an aluminum line of the wiring. In order to still ensure optimum electrical conductivity, an end section of the aluminum line may be connected to an electrical contact element containing a noble material, such as copper, which oxidizes less easily.
When aluminum and copper are in contact in the presence of an electrolyte such as salt containing water, galvanic corrosion will occur due to the rather large difference in the standard electrode potentials of aluminum and copper. This corrosion will lead to the consumption of the material having the lower standard electrode potential (here aluminum) and/or to the creation of a gap between the wire electrical cable and the electrical contact element, ultimately resulting in a poor quality of the contact between the wire electrical cable and the contact element.
Previous attempts to reduce corrosion were directed to inserting at least one intermediate layer between the wire electrical cable and the electrical contact element, with the at least one intermediate layer containing a material having a standard electrode potential ranking between the standard electrode potential of the wire electrical cable material and the sheet metal material of the electrical contact element.
In order to reduce corrosion even further, an additional layer was arranged between the electrical contact element and the at least one intermediate layer, with the additional layer comprising a material having a lower standard electrode potential than the sheet metal material of the electrical contact element and the material contained in the intermediate layer. The material of the additional layer thus exhibited the lowest standard electrode potential of all layers and therefore would be preferably oxidized, i.e. the additional layer consisted of an easily corrodible material. By corroding, the additional layer protects not only the intermediate layer but also the electrical contact element and the wire electrical cable against corrosion. However, as corrosion of the additional layer gradually proceeds, an electrically insulating layer is formed which in turn will increase the electrical resistance between the wire electrical cable and the electrical contact element and thereby deteriorate the quality of the contact between the contact element and the wire electrical cable.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.